Master/slave communication interface systems exist for a variety of applications. As an example, position encoders can implement master/slave communications systems in which a master microcontroller can request position data that is provided from a slave microcontroller. The transfer of data over the master and slave microcontrollers can be clocked to ensure that the data is properly interpreted by the associated microcontroller device. As an example, the master/slave communication interface system can be configured as a synchronous communication interface system in which a selected frequency clock signal is transmitted with the data over separate wires relative to the data. As another example, the master/slave communication interface system can be configured as an asynchronous communication interface system in which the data rate of the signals transferred between the master and slave microcontrollers is fixed.